Children's Mercy Hospitals and Clinics (CMH), located in Kansas City, MO. is a large, comprehensive pediatric medical center and the only free standing children's hospital between St. Louis and Denver. CMH provides state-of-the-art care for children from 18 primary counties in Missouri, Kansas and adjoining areas with a total population approaching 2.5 million. In 2009 CMH established an active population-based surveillance system through Centers for Disease Control and Prevention (CDC) funding mechanism from American Recovery and Reinvestment Act. The CMH active surveillance system can be effectively utilized to study the impact of new or upcoming vaccines and policies relating to vaccination. Our active surveillance system will monitor community rates of acute gastroenteritis (AGE) and acute respiratory illness (ARI) by prospectively enrolling children year-round in both our outpatient and inpatient locations. Our two model projects are described below: First model project: Our first model project will examine rotavirus vaccination effectiveness through population-based, laboratory confirmed, active surveillance. Specifically, we will prospectively monitor rotavirus disease burden and characterize rotavirus genotypes. Parents of the AGE children and control subjects will be consented to participate in the study;a stool specimen (only for AGE children) and permission to access vaccination record will be requested. Stool specimen is tested in CMH laboratory for rotavirus antigen and positive specimens will be shipped to CDC for genotyping. Rotavirus vaccination record will be accessed through Kansas and Missouri vaccination registries, CMH electronic medical records or by contacting primary care provider. Rotavirus vaccine effectiveness will be calculated by comparing rotavirus positive to rotavirus negative or control children. Second model project: The goal of our second model project is to understand the epidemiology of human parechovirus (HPeV) associated AGE. HPeV is a newly described virus closely related to enterovirus (EV). The majority of the newly described HPeV types (17 types) have been isolated from diarrheal stool specimens obtained from children around the world. HPeV is also associated with respiratory illness and central nervous system infection in infants. The evaluation of the burden of HPeV associated infections in the US currently is limited to a passive surveillance system and a few ad hoc studies in academic centers. We have recently demonstrated a high burden of HPeV3-CNS infections (18%) in US children during 2007 and 2009 (Selvarangan et al 2010;appendix 3). The proposed NVSN network can be effectively utilized to understand the epidemiology of this newly recognized viral pathogen. The specific questions we can address include: 7 Incidence of HPeV in diarrheal and respiratory stool specimens in children 7 Clinical presentation associated with HPeV infections 7 Discovery of new HPeV types in collaboration with CDC, Picornavirus laboratory 7 Association of currently circulating HPeV types with specific illnesses CMH's previous success enrolling subjects in NVSN demonstrates our capabilities. Notably, CMH has the flexibility and capability of extending surveillance to other vaccine preventable diseases, demonstrated ability to collect stool specimens and rotavirus vaccination data on subjects enrolled in the study, ability to access hospital admission data, and two years of rotavirus surveillance data from our participation in NVSN. PUBLIC HEALTH RELEVANCE: The Children's Mercy Hospital population-based active surveillance system is engaged in evaluation of the impact of new or upcoming vaccines. Real-time surveillance data generated from our surveillance efforts will allow us to better understand the epidemiology of new and emerging gastrointestinal and respiratory pathogens targeted for control through vaccination practices.